The present invention relates to refrigeration chillers. More specifically, the present invention relates to the cooling of compressor lubricant in a refrigeration chiller. With still more specificity, the present invention relates to the cooling of compressor lubricant in a refrigeration chiller by chiller system refrigerant sourced from and returned to the chiller's condenser by thermosiphonic effect.
Refrigeration chillers employ compressors of varying types to compress a refrigerant gas which is first condensed and then vaporized in the process of cooling a heat load. Such compressors most typically have rotating elements that are supported for rotation in one or more bearings that require lubrication in order to function. The reliability of the bearings and, therefore, the overall reliability of the chiller is enhanced by cooling the oil used to lubricate the bearings prior to its delivery to the bearing surfaces.
There are a great many methodologies and various apparatus by which oil cooling in a refrigeration chiller has been accomplished. Many cooling mediums, many and different kinds of heat exchangers and many and different motive forces by which to move the oil and the medium by which it is cooled into heat exchange contact have been employed. Many times, at least the flow of the medium by which oil has been cooled in refrigeration chillers has required the use of a pump, eductor or other mechanical or electromechanical apparatus which, in turn, adds expense to and/or complicates the chiller fabrication process and/or requires the use of valving and/or controls. The use of such mechanical or electromechanical apparatus, valves and/or controls associated with the oil cooling process also brings with it potential failure modes that detract from the overall reliability of chiller systems.
The need therefore exists for apparatus and a method, for use in a refrigeration chiller, by which to cool the oil which lubricates the bearings of the chiller's compressor where such apparatus and methodology are essentially fail-safe and do not require the employment of mechanical and/or electromechanical apparatus, valving and/or controls to cause the flow of the lubricant cooling medium into heat exchange contact with the lubricating oil that requires cooling.